Radio frame and the like



Dec. 31, 1940. SCHRACK RADIO FRAME AND THE LIKE Filed Oct. 4, 1938 2.Sheets-Sheet l INVENTOR EDUARD SCHRA c/ g/M'V L- N Y Zlii RADIO FRAME AND THE LIKE EDUA RD SCHRA CK A TTORNEY Patented Dec. 31, 1940 UNITED STATES RADIO FRAME AND THE LIKE Eduard Schrack, Vienna, Germany, assignor to 2 Radio Corporation of America, New York, N. Y.

Application October 4, 1938, Serial No. 233,241

In Austria November 30, 1937 5 Claims.

In the manufacture of radio-receivers and the like it is not easy to satisfy in a satisfactory manner. both the condition of cheap mass-production and of a quicker adaptability of the model to the requirements of the market evenin the case of comparatively small production-quantitles.

In the usual chassis-constructions there are complicated and expensive tools for punching and for modelling the chassis required which are only remunerative in the case of a. very important production. On the other hand the use of these chassis tools has already necessarily determined in all details a very definite construction method and arrangement so that a subsequent deviation from the original construction plan or the introduction of improvements is out of question.

To avoid this evil it has already become known, it is true, to use for the internal electrical construction of the receiver, circuit elements which are manufactured in series and then combined to a radio-set meeting the requirements. This construction, however, has not been favorably received in practice for the reason that the sets manufactured in this manner were heavier and have a lower efiiciency than those designed already beforehand for a certain use.

The present invention has for its purpose to provide a construction method for radio-chassis or the like, in which the advantages of theseriesproduction of circuit elements are fully maintained and a final product is obtained which is nevertheless at least equivalent, but ingeneral superior as regards utilisation of space and efficiency even-to the special sets designed beforehand for a certain use.

The invention departs from the usual practice of juxtaposing the supports of the circuit-elements exclusively in the same plane, due to which the whole arrangement extended in substantially two directions. Also in sets constructed with a single chassis without use of circuit elements the arrangement, apart from the inorganic addition of parts, extended principally in two directions.

According to the invention, however, the circuit elements are arranged in several planes, preferably in parallel with one another so as to constitute together a three dimensional complex which naturally results in a much more compact model of the whole set. In thisseteach circuitelement is mounted on a substantially plane arrangement-support, for example within. a frame or on an insulating plate and comprises a group of construction parts (coils, resistances, condensers, switches, etc.) electrically connected elements.

and corresponding with each other from the point of view of circuiting. Radio-receivers having construction parts arranged in three directions are known, it is true, but these had an entangled wiring, due to which the inspection dur- 5 ing manufacture and the possibility of obviating faults was much impeded. The three dimensional utilisation of space is obtained according to the invention in such manner that a clear difierence is made between circuit elements and 1 feed conductors and that the feed conductors extend transverselyto the planes of the arrangement-supports ofthe circuitelements. In the sense of the invention it is not necessary to provide a particularly shaped circuit element for 15 each function (high-frequency, detector, inter- .medlate frequency, low frequency amplification,

etc.), but use is made of circuit elements which in spite of different functions are largely identical in their fundamental construction. It is'120 particularly advisable that the circuit supports should have the sameshape for all of the circuit The connections betweenjthe individual ccnstruction parts of eachcircuit element are pref-6 25 erably' established by means" of metal strips.

Such metal strips as connection leads-have already hecome known in weak-current .technics, but-their application in the scope of the" present :invention gives'very special advantages: If 'in: 30

sulating plates are used as circuit-supports; the metal strips can; be arranged on themand for example besecured bymeans ofleyelets or by means of riveting; they may also be embedded in grooves in the insulating. plate. An advan-l 35 'tageous ,form of construction consists in that these metal strips are bakelised in an insulating plate of artificial resin, that is, the strips are embedded in the plate so that when the pressure and heat treatment is applied they are firmly: 40 fixed in position. -Co-mpared-with the use of wires, the use of metal strips has the advantage that the total leadson one side of each arrangegment-support may be stamped-from tin-foihin which. cross pieces are left between the strips so 45 that the leads form a mechanically coherent network. This network is united with the insulating-plate, for example in such manner that it, is arranged on the insulating plate and con- .nected to. the latter at a higher temperature: 5

under pressure or it is embedded into the insulating' plate during manufacture thereof... The cross-pieces which are superfluous now, are then removed which can be done very easily by means of punching'or drillingand this in such manner;

that a hole is produced at the corresponding point in the insulating plate. By means of a suitable arrangement of the leads it is possible to arrange the leads within each circuit element so that the circuit-support is only provided with leads on one side, thus simplifying the assembly and reducing the capacity of the leads. Instead of stamping the leads from metal .strips, they may also be manufactured by applying metal coatings with the aid of the templets.

The advantage of these methods of manufacturing leads consists in that the different sets of one batch have no great strays or lead capacities; furthermore the process of circuiting the set which constitutes an important part of the production, is much simplified and faulty connections are avoided. Sh0rt-circuits between leads which otherwise could arise through shocks during use, are impossible in this circuit arrangement.

In order to make the electrical joints of the elements required forthe supply an'd for establishing'the relative connections, simple andclear from the point of view of manufacture, these are not branchedat will from any points of the circuit elements, but led substantially in the plane of the circuit-support of each circuit element to one or several of its sides and are-connected to the feed conductors at that point or in the extension of the'planeof the circuit-support. By feed conductors are to be understood'hereinafter all of the electrical connections of the set not corresponding to the circuit elements, i. e., especially connections to the electrodes of amplifier tubes, connections to the voltage supplies, control potential connections and the like. The feed conductors with all their corresponding essential construction parts are also preferably concentrated to one or more construction-elements.

Such a concentrated unit will be called feed element hereinafter.

The leads in the feed-elements may be made similarly to those in the circuit elements; in these elements 'manyconnections may be formed directly by the individual construction "parts.

The invention will be more clearly understood with-reference to the accompanying figures showing one embodiment thereof.

Fig. 1 shows a circuit elementmounted' on an insulating plate having metal stripsas connection leads.

Fig. 2 represents the same circuit elements, in whichthe construction parts, however, are indicated by=their electric symbols.

Fig. 3 is the axonometric'view of the arrangement of the circuit elementsand the-corresponding feed-element.

Fig. 4 gives the view of -a protecting case seen on top after removing the fee'd-element.

Fig. 5 is an axonometric view of the total arrangement of a radio-receiver chassis according to the invention.

Fig. 1 shows a circuit support I formed by an insulating plate (for example artificial resin) whose dimensions are approximately 10x10 cm. A number of corresponding construction parts are mounted on thisplate in such manner as to save space,'i. e, the coils2 and 3having an iron core and the air-coil 4; the connecting condensers 7 5, 6 and 1 (trimmer condensers) and the padding condensers 8 and 9, together with a commutator for change-over of wave length. The coils with iron core'in this'form-of construction are made in such manner that the turns are supported'b-y 75 a little Bakelite cylinder, into which a core of the padders 8, 9 being constructed so that the two electrodes are formed by a wire inserted into or 5 wound on an insulating tube. For the switch a circle is cut out in the insulating plate I, over whose edge circuit springs i0 project on both sides of the plate. These are connected meeting the requirements by means of contacts ll ar- 10 ranged in a revolving circle disc l2 of insulating material. After assembly of the individual circuit elements the shaft of the wavelength switch is passed through the slit 13 provided in the circle disc. The connection of the leads of the circuit elements to the feed conductors is done on the side M of the insulating plate I.

The connection leads between the individual construction parts are indicated in Fig. 1 by l5 and I6; the leads I5 on the front are strongly 30 drawn out, whilst those on the back 16 are drawn dotted'and dashed. The diagram of the arrangement shown in Fig. 1 is represented in Fig. 2, in which equal reference as in Fig. 1 indicate equal parts. 25

The circuit element as representd in this figure is intended for the oscillator stage of a superheterodyne receiver, but the same circuit-support may also be used practically for the high-fre- I quency preliminary stages or for the intermediate frequency stage.

In all events groups of coils and condensers of similar kind may be used. The coils may consist, for example, of aperiodic turns coupled to the proper resonance coils of the corresponding group of coils. 'It is advantageous tomake the lead connections equal for-ail of these applications and to leave disconnected any connections not re-- quired,and alternatively to shortcircuit them or to remove them in the manner mentioned above. F0 According to the form of construction shown in Fig. 1, the amplifier tube belonging to the corresponding stage is not'included in the circuit element. This .is advantageous in many cases to obtain a concentrated spatial arrangement of the 4 circuit elements. Furthermore an amplifier tube is, according to:its nature, 'thecoupling member between the different circuit elements and may therefore in many cases be deemed to belong to one as'well as to the other circuit element. In the 50 present form of construction the amplifier tubes are included in the feed-element. It is not essential for the invention, however, that the amplifier tubes are not included in the circuit elements. In certain cases the tubes may be built advantageously into the circuit elements, for example when using the so-called'button tubes, in which the lead-through wires run radially from the equator of a bulbor acorn-shaped glass tube. These conductors of thebutton tube are arranged 60 therefore in one plane and may preferably'be removed to the plane of the circuit-support of the circuitelement. In Fig. l, for example, a button tube with radial lead-through wires may be provided, for example, instead of the multiple switch shown in this figure. This is particularly advisable if the setmust not be allowed to be connected'for a plurality of wave-lengths, such as in the case of television reception.

Although Fig. 1 shows that all of the connections to the feed conductors are conducted over the side I 4 of the circuit element, this is not absolutely necessary in the sense of the present invention. It is also possible to make individual connections directly from the corresponding construction part. 7 Thus the grid supply conductor of a button tube, for example, is in some cases not led out at the equator, butat a terminal of this tube. This lead must then not be led overthe side of the circuit element, but may be connected by the shortest way to the corresponding construction part of the subsequent construction part or feed-element.

Fig. 3 shows schematically an axonometric view of how the circuit elements may be coupled to the feed-elements. The circuit elements 11, etc.,are arranged in parallel one with another and project with their sides l4 through the plane of the feedelement l8. To enable this, slits I9 are provided in the circuit support ofthe feed-element l8 constituted by an insulating plate, so that the sides [4 may pass through this slit. 3 shows two groups of circuit elements arranged one next to another; each of them is constituted by three circuit elements arranged in parallel one after another. Three out of them, i. e., the left hand group are represented in'the drawings. The shaft 20 of a commutator passes through this whole group of circuit elements. This enables that also complicated wavelength circuits may be effected with a comparatively shortshaft and that all parts to be commutated (coils, etc.) may be arranged in direct proximity of the corresponding circuit contacts. The commutator shaft may be drawn out so that it is only inserted after assembling of the set; this construction is also advantageous in case of repairs. The tube holders or sockets 2| are arranged on the feed-unit 18 in the plane of their circuit-support and this in such manner that each tube is positioned between the circuit elements connecting them. The tubes are thus spatially concentrated in the set, whilst the sensitive tube conducting leads are nevertheless shorter than was possible in the usual receiver chassis. The resistances which serve for the production of the necessary voltage drops, control potentials etc.; are mounted, in addition, on the circuit-support oi' the feed-element l8. Also transversal connections between the two groups of circuit elements may be led over the feed element I 8', which are advantageous, for example, with band-width control.

The individual construction parts of a circuit element are preferably concentrated so as to make mutual screening superfluous. However, it will be advantageous or necessary in general to isolate the individual circuit elements mutually by means of metallic walls. Fig. 4 shows how this isolation may be carried out advantageously from the point of view of manufacture. In this figure will be seen a metal casing 22 divided by means of partition walls 23 in six compartments, each of which having in its centre a longitudinal groove or the like for inserting the circuit-support I1. Each circuit element can therefore be easily assembled; it is pushed then into the metal casing 22, whereupon the feed-element is placed on the casing 22 as closing cover, so that the sides [4 (Fig. 3) of the circuit elements pass through the slits l9. The electrical connection of the circuit elements to the feed-conductors may be very easily established now, for example, by soldering or simply by clamping.

Finally Fig. 5 shows diagrammatically in axonometric view the total construction of the chassis of a radio-receiver according to the invention, viz., a superheterodyne receiver having three ranges of wavelengths. The metal casing 22 comprises again two groups each consisting of three circuit elements, whosesides-M pass through the insulating plate l8 of the feed-element. Also the sockets of the amplifier mixing or rec'tifier'tubes'25 are arranged on the feed element. The metal casing 22 carries the triple variable condenser 26. The shaft extremities of a wavelength switch 205a band. width control device 3|, the volume control device 21 and the sound corrector 28 project from the metal casing 22. These shafts may be operated-in known manner, for example, by means of Bowden cables or the like in the desired combination of control knobs on the casing of the set. In the present form of construction additional devices are provided on both sides of the arrangement according to the invention constituted by circuit elements and feed-elements, in which 29 designates a low-frequency output stage and 30 a high-voltage unit. The mounting plates of bothof these stages are in equal height with'the feed element so that the connection of these stages to the chassis according to the invention can be easily establishedby means of wires or by means of metal strips.

The arrangement according to the invention is in no way bound to the described form of construction, but may also be used in other sets. As exhibited by the form of construction described, there are besides the advantages of a compact construction and simplification of having stocks, some further, very important advantages. For example, any fault is now impossible in making the electric connections which was always done so far by hand. The connections must be automatically established correctly, since in coupling the circuit elements with the feed-element the connecting points automatically fall together. It is not essential that all of the supply conductors are mounted on one feed-element. It is also possible to provide several sides of each circuit element for the connection of the supply conductors. Another fundamental possibility consists in making the circuit-supports of the circuit elements, for example, circle-shaped and to provide the supply conductors on the wall of a cylinder surrounding the circuit elements outside.

Another advantage of the arrangement according to the invention is the high electric stability. Whilst in the usual freely conducted connections the individual copies of a set manufactured in series showed mutually considerable differences as regards self-capacities of the arrangement of the leads, this stray is now reduced to a minimum. As a result of this it is possible to maintain the correcting values (trimmer condensers, variable iron cores, etc.) very small so as to make them superfluous in many cases.

The distance of the planes of subsequent circuit elements may be made as small as is allowed by the size of the construction parts, taking into account the subsidiary damping through the screening sheets, if any. It has been found in practice that the planes of the individual circuit elements may be approached towards one another at a distance of approximately 5 cm. or even smaller without affecting the quality of the set.

What I claim is:

1. In a radio chassis, a plurality of unitary structures each comprising an individual portion of a radio circuit, each of said structures including a group of related interconnected circuit elements mounted on an individual panel,

the connections between the circuit elements 76 mounted on. any one of said panels being provided by a plurality of: conductive members laid on a face of the panel, a main panel, a plurality of tube sockets mounted in openings provided on said main panel, means for mounting said individual panels edgewise on a face of said main panel and connections between the conductive members on said individual panels and said tube sockets.

2. In a radio chassis as described in claim 1, wherein at least two of said individual panels include individual variable elements, ashaft for operating said variable elements in unison, openings in said two individual panels for receiving said shaft, said two individual panels being mounted on said main panel in parallel relationship and so that the openings formed in said individual panels register with one another.

3. In a radio chassis as described in claim 1, wherein the main supporting panel includes a plurality of electrical elements to be connected to various ones of the conductive members of the individual panels, means for mounting said individual panels edgewise on a face of said main panel and in parallel relationship with each other, and slits formed in said main panel in the vicinity of the points where the individual panels are mounted, some of said conductive members being passed through said slits for connection to the electrical elements mounted on the -main panel.

4. In a radio chassis as described in claim 1, wherein a plurality of electrical elements are mounted on said main panel, means for connecting some of said conductive members to some of said electrical elements, means for mounting said individual panels on said main panel so as to form atier-like structure, and metallic sheets between said individual panels for shielding the circuit elements of each panel from the circuit elements of the others.

5. Ina radio chassis, a plurality of substantially similarly shaped assembled units corresponding to different parts of a radio circuit, each of said units including an auxiliary panel on which the circuit elements making up the particular portion of the radio circuit corresponding thereto are mounted, conductive members laid on each of said auxiliary panels for providing the connections between various ones of said elements, at bed-plate on which other elements of the radio apparatus are mounted and means cooperating with said auxiliary panels and the bedplate for mounting said auxiliary panels on the bed-plate in spaced relationship, conductive means 101" connecting certain of said conductive elements of the auxiliary panels to certain ones of the elements mounted on the bed-plate, said bed-plate being provided with openings through which said conductive means pass.

EDUARD SCI-IRACK. 

